Entity features - Dark shadows with shaders and transluscent in GUI

[desert gazelle]

Hello!
I would like to have some help with entity features. I've began to test around with shaders and entities in the GUI and I'm noting some weird behaviors.

1. In the GUI, the features seems to blend with the background. When they are on the skin itself, they are solid and works perfectly fine. But as soon as it's a feature it seems to be translucent and take the background colors into account.

2. With shaders, the features have very dark shadows. I've tested with Bliss and Complementary and both create the issue. While for the body it works fine, the features get very contrasty shadows.

Any of you have an idea of what could cause this issue?

Here's some more information about the project :

• Using fabric 1.21.8.
• Npc features/visuals are added on top of each others using layers.

Npc Renderer :
https://github.com/Jukoz/middle-earth/blob/registry-rework/middle-earth/src/main/java/net/sevenstars/middleearth/entity/npcs/NpcEntityRenderer.java

Ear Feature Renderer (All of them does the same behavior, but the ear is what's shown in the screenshots) :
https://github.com/Jukoz/middle-earth/blob/registry-rework/middle-earth/src/main/java/net/sevenstars/middleearth/entity/npcs/features/ear/EarFeatureRenderer.java

Please ping me when answering (reply or @)

Thanks a lot in advance!

-# How it's supposed to be :

In the GUI :

With shaders :